As is well known, blood is composed of plasma and cell ingredients (i.e., erythrocytes, leukocytes, thrombocytes, etc.). The volume percentage of erythrocytes based on the volume of whole blood is called the hematocrit value, which is an important value to know in assessing the degree of anemia. Methods for determining the hematocrit value (hereinafter abbreviated as "HCT") that have so far been utilized include a centrifuging method, an electrical resistance method, a specific gravity-measuring method, etc. However, these methods have the defects that a long time and complicated wet procedures are required to conduct these methods.